1. Field of the Invention
The present invention relates to a structure of a covered wire for providing water cutoff to the covered wire by sandwiching the covered wire constituted by covering core lines by a water cutoff member made of a resin to subject to ultrasonic welding.
2. Related Art
In reference to FIG. 12 and FIG. 13, in a related art, there is a water cutoff structure of a covered wire 30 for carrying out a water cutoff processing by sandwiching the covered wire 30 by a pair of upper and lower water cutoff members 31 made of a resin in FIG. 12 and applying an ultrasonic wave from an upper side of FIG. 12 of the water cutoff member 31 by an ultrasonic welding horn 32 to thereby weld the water cutoff member 31 to core lines of the covered wire 30 (refer to Japanese Patent Publications Nos. JP-A-7-320842 and JP-A-11-250952).
Each of the water cutoff members 31 is formed to be larger than a widening width of the core lines of the covered wire 30 after ultrasonic welding. Thereby, in ultrasonic welding, the molten resin of the respective water cutoff members 31 is filled among the core lines of the covered wire 30 to ensure a water cutoff function.
According to the above-described water cutoff structure of the covered wire 30 of the related art, with an increase in a size of the covered wire 30 to be subjected to water cutoff, also a size of the water cutoff member 31 needs to increase in direct proportion thereto. Therefore, there poses a problem that downsizing thereof is difficult.
Further, when a small water cutoff member is used to achieve downsizing, there poses a problem that crack is liable to cause and a sufficient water cutoff function cannot be achieved.
Further, there poses a problem that time is taken in ultrasonic welding and an increase in cost is unavoidable.